A check processing system includes a transport to convey checks through the system and a scanner to image the checks. The check processing system includes a feeder that moves checks through the system to a first tray for processed checks and a second tray for rejected checks. Checks are rejected when they are processed as double feeds, meaning the system detects the possibility that more than one check is present. Some check processing systems use ultrasonic double feed detection by passing an ultrasonic wave through checks as they pass. Some checks are included in carrier envelopes, such as when a check is damaged. The check processing system using the ultrasonic double feed detection processes the carrier envelope as a double feed due to the multiple pieces of paper involved in using a carrier envelope.
In cases when the status is not automatically be determined, a user is prompted to override the exception or to reject the item. Overrides continue scanning, while rejected items cause a double feed detection exception requiring the item to be reprocessed. The check processing system is not always able to determine whether an item is hiding behind a carrier envelope or if the item in the track is a carrier envelope that failed automatic detection. With busy operators who may normally override, it is possible that they will make the wrong selection. The cost of a missed true double feed means delays and reprocessing. In some operations that are branch scan and go operations, the balancing happens in another location, there is significant time lost in finding the error and fixing it. High dollar items cause lost interest and float money due to delays.